Alex Ovechkin scored four goals to become the first player in 100 years with back-to-back hat tricks to open a season, and Washington Capitals beat the Montreal Canadiens, 6-1, on Saturday night in Washington.

Ovechkin had three goals in the third period in Thursday’s opening night win at Ottawa, then matched the feat while helping chase Montreal goalie Carey Price in the first period Saturday. He added his fourth goal at 16:46 of the second period against Al Montoya.

It was the fourth four-goal game of his career and second against the Canadiens.

Braden Holtby stopped 38 shots and T.J. Oshie also scored for Washington.

Ovechkin opened the scoring 20 seconds in, added his second goal at 2:51 and his third at 18:10. Evgeny Kutnetsov assisted on all four of Ovechkin’s goals. Nathan Walker became the first Australian native to play in the NHL and had a grand debut when he scored Washington’s sixth goal late in the second period.

Oshie gave Washington a 2-0 lead 46 seconds into the game, and the Capitals led 4-0 after one.

The goal was originally credited to Devante Smith-Pelly, but when the change was announced to the crowd during the third period, some fans waved Australian flags in Walker’s honor.

Brendan Gallagher beat Holtby early in the second period for Montreal’s only goal.

Price allowed four goals on 14 shots. Montoya followed with seven saves.

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Jared McCann scored the tiebreaking goal in the third period after a review overturned the initial ruling of goalie interference, and the Florida Panthers beat the Tampa Bay Lightning, 5-4, in Sunrise, Fla. Lightning forward J.T. Brown raised his right fist during the playing of the national anthem before the team’s first road game of the season.

Brown, who was scratched for Tampa Bay’s season-opening win against Florida, remained standing throughout the anthem Saturday night. Brown, one of approximately 30 black players in the NHL, used the same protest before a preseason game against the Panthers last month.

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In other notable games Saturday, Hobey Baker Award winner Will Butcher set up three power-play goals to steal the spotlight from No. 1 overall draft pick Nico Hischier, and the new-look Devils opened the season with a 4-1 victory over the Colorado Avalanche in New Jersey . . . Tyler Bozak, Leo Komarov and Nazem Kadri scored third-period goals and the Toronto Maple Leafs held off the New York Rangers, 8-5, in their wild home opener.

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Jaromir Jagr decided not to play in the Calgary Flames’ home opener Saturday against the Winnipeg Jets.

After arriving Wednesday from the Czech Republic, Jagr had only two practices and the pregame skate Saturday with his new team. Coach Glen Gulutzan said when Jagr plays the first game of his 24th NHL season is his decision.

‘‘He said he felt a lot better the second day than he did the first and that he probably needs a couple more skates, good skates,’’ Gulutzan said. ‘‘I thought he was very good yesterday, for a 45-year-old guy to come in with no training camp. He was arguably one of our best guys yesterday, but he needs a couple more days to get up to game speed.’’

Second only to Wayne Gretzky in NHL scoring with 1,914 points, Jagr signed a one-year, $1 million contract with the Flames. If he plays 57 games, he’ll pass Gordie Howe’s record of 1,767.